Jump to content
The mkiv Supra Owners Club

Cam Shimming -- Tomei Poncams


Jellybean

Recommended Posts

Hey

 

I had a read of Scotts thread, problem is I dont half a clue what I am doing

 

http://www.mkivsupra.net/vbb/showthread.php?254960-How-to-Re-Shim-Cams

 

I bought Tomei PonCams

 

Do I need to re-shim, why do you need to re-shim? I am not doing it but my mechanic was wondering why I asked him about re-shimming, I just seen other guys suggested it but my mechanic has experience with Tomei Poncams so maybe they are different setup to other brands

 

http://www.tomeiusa.com/_2003web-catalogue/e087_cam_1j_2j.html#early2j

 

http://www.tomeipowered.com/BTE/index.php/2012/04/26/new-adjustable-pulley-for-toyota-1jz-2jz-engines/

 

 

■PRECISION GRINDS

■PRESET VALVE TIMING centerline to 110 degrees

■STABLE IDLING

■BEST BALANCE

■PERFORMANCE THROUGHOUT

■OUTSTANDING TURBO RESPONSE

■STOCK VALVE SPRING COMPATIBLE

Link to comment
Share on other sites

You need to check the shim to lobe clearances, using feeler gauges. If any don't meet the spec from the bgb, you remove the shim and measure it using a micrometer. Then work out how much bigger or smaller the shim would need to be, to be correct.

It's a simple job, but time consuming.

 

Toyota sell shims in a huge range of thicknesses, for a few £ each. Just go to your local parts counter armed with the required sizes :thumbs:

Link to comment
Share on other sites

Every cam is different, your car is shimmed based on the cams installed. When you change the cam, you need to change the shims. The fact your mechanic doesn't know this would worry me on its own.

 

You need to check the shim to lobe clearances, using feeler gauges. If any don't meet the spec from the bgb, you remove the shim and measure it using a micrometer. Then work out how much bigger or smaller the shim would need to be, to be correct.

It's a simple job, but time consuming.

 

Toyota sell shims in a huge range of thicknesses, for a few £ each. Just go to your local parts counter armed with the required sizes :thumbs:

 

The shims are actually extortionate for what they are. Approx £10 each IIRC.

 

- - - Updated - - -

 

There about £12 each. !! I know, I ended up buying from the states as it was much cheaper. John hodge has loads of my spares, so drop him a msg if you need a few.

 

Beaten to it lol. I managed to mitigate most of them by swapping them around. It was a bit of a job though :D

Link to comment
Share on other sites

There are alternatives to buying shims, but you need workshop equipment. You can grind thick shims thinner, so long as you don' take so much off as to risk getting through the surface hardening. Not sure how deep that is, so I play it conservatively. You can also grind the valve tips, but it must be done in a fixture to hold them 90 degrees to the (perfect finish) wheel. Converting to MR2 Gen III turbo lightweight buckets and top hat shims is another possibility if you want to play race engines :)

Link to comment
Share on other sites

As Chris mentions, I've also successfully ground shims down, when it was very minor adjustments needed. From memory, only the top side is hardened, so you grind the underside.

 

Pretty sure I've also heard rumours of 1zz buckets and shims fitting too.

 

I personally prefer the shim over bucket setup, makes it much easier to swap shims if/when necessary. It only becomes necessary to go shim under, when the rev limit is raised

Link to comment
Share on other sites

As Chris mentions, I've also successfully ground shims down, when it was very minor adjustments needed. From memory, only the top side is hardened, so you grind the underside.

 

Pretty sure I've also heard rumours of 1zz buckets and shims fitting too.

 

I personally prefer the shim over bucket setup, makes it much easier to swap shims if/when necessary. It only becomes necessary to go shim under, when the rev limit is raised

 

Honestly how much would you want to raise it? We are having Limits around 8500 with the stock buckets and shims. 264 and 272 Cams work fine like that with Stiffer Springs(and if you want retainers). Eventually with bigger cams and even more Revs i'd aggree to the conversion but for most builds its unnecessary. :)

Link to comment
Share on other sites

Agreed, but if someone likes to extend their knowledge by building a head that's a bit more "racy"it's a viable option to see what the next step is. Personally I wouldn't bother with a relatively slow revver.

 

I just got the book you recommended by Graham Bell Four-stroke Performance Tuning

 

I will have her singing soon!

Link to comment
Share on other sites

Honestly how much would you want to raise it? We are having Limits around 8500 with the stock buckets and shims. 264 and 272 Cams work fine like that with Stiffer Springs(and if you want retainers). Eventually with bigger cams and even more Revs i'd aggree to the conversion but for most builds its unnecessary. :)

Unnecessary?

 

Not sure what you mean bud. If you mean changing to shim under bucket, I'd agree.

Link to comment
Share on other sites

  • 1 month later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.